Authorities say the hour at which the accident happened and the route the vehicle was taking suggests the people in the bakkie may have been trying to evade authorities.

The department says the 15 passengers of the double cab bakkie and its driver were all identified as Zimbabwean.

However, preliminary investigations suggest only four of them were in the country legally.

The department's Kagiso Mootane says, "It's unfortunate because if you remember, during December we arrested a lot of them. We deported them back to Zimbabwe but what is worrying is in cases like this one, they come back illegally."

Only one of the passengers of the bakkie survived while the truck driver sustained minor injuries.